Shanessa is a variant of the name Shanesa, which is of English origin. It is derived from the name Shanes, which is believed to be of Celtic or Irish origin. The name Shanessa is associated with the Gaelic word shane, meaning warrior or strong. In the Middle Ages, the name Shanessa was introduced to England by the Normans, where it became a popular name among the nobility. Over time, the name Shanessa evolved into various spellings, including Shanessa, Shanessah, and Shanessa. Today, the name Shanessa is still used in many countries, including the United States, Canada, and Australia.